Memory device and memory circuit

1. A memory device, comprising: a spin-orbit torque (SOT) layer; a magnetic tunnel junction (MTJ), standing on the SOT layer; a read word line, electrically connected to the MTJ; a selector; and a write word line, connected to the SOT layer through the selector, wherein the write word line is electrically connected to the SOT layer when the selector is turned on, and the write word line is electrically isolated from the SOT layer when the selector is in an off state, wherein the selector is a two-terminal selector, with one terminal connected to the SOT layer and the other terminal connected to the write word line.

2. The memory device according to claim 1 , wherein the read word line is connected to the MTJ by a conductive via in physical contact with the read word line and the MTJ.

3. The memory device according to claim 1 , wherein the selector is a threshold-type selector, an exponential-type selector or a mixed type selector having a threshold characteristic of the threshold-type selector and an exponential characteristic of the exponential-type selector.

4. The memory device according to claim 1 , wherein the MTJ is electrically connected to the read word line through a conductive via, and a sidewall of the MTJ is substantially coplanar with a sidewall of the conductive via.

5. The memory device according to claim 1 , wherein a first conductive via is electrically connected to the SOT layer and the first terminal of the selector, and a second conductive via is electrically connected to the write word line and a second terminal of the selector.

6. The memory device according to claim 1 , wherein a conductive via is electrically connected between the write word line and a first terminal of the selector, and a second terminal of the selector is electrically connected to the SOT layer without a conductive via in between.

7. The memory device according to claim 1 , wherein a conductive via is electrically connected between the SOT layer and a first terminal of the selector, and a second terminal of the selector is electrically connected to the write word line without a conductive via in between.

8. The memory device according to claim 7 , wherein the selector is formed as a pillar standing on the write word line.

9. The memory device according to claim 7 , wherein the selector is in a line shape, and the selector and the write word line extend along the same direction.

10. The memory device according to claim 1 , further comprising a bit line, wherein the bit line is electrically connected to the SOT layer, and a portion of the SOT layer on which the MTJ stands is located between a portion of the SOT layer to which the bit line is connected and a portion of the SOT layer to which the selector is connected.

11. The memory device according to claim 10 , wherein the MTJ and the read word line are connected to the SOT layer from above the SOT layer, and the bit line, the selector and the write word line are connected to the SOT layer from below the SOT layer.

12. The memory device according to claim 10 , wherein the bit line, the MTJ and the read word line are connected to a first surface of the SOT layer from above the SOT layer, and the selector and the write word line are connected to a second surface of the SOT layer from below the SOT layer.

13. The memory device according to claim 10 , wherein the bit line is connected to a first surface of the SOT layer from below the SOT layer, and the MTJ, the read word line, the selector and the write word line are connected to a second surface of the SOT layer from above the SOT layer.

14. A memory device, comprising: a spin-orbit torque (SOT) layer; a magnetic tunnel junction (MTJ), standing on the SOT layer; a first word line, electrically connected to the MTJ without a selector in between; a second word line, selectively in electrical contact with the SOT layer; and a bit line, electrically connected to the SOT layer, wherein a portion of the SOT layer on which the MTJ stands is located between a portion of the SOT layer to which the bit line is connected and a portion of the SOT layer to which the second word line is selectively in electrical contact.

15. The memory device according to claim 14 , wherein at least one of the bit line and the second word line extends at a first side of the SOT layer, and the MTJ and the first word line are located at a second side the SOT layer opposite to the first side.

16. A memory circuit, comprising: a plurality of magnetoresistive storage units, arranged as an array, and respectively configured to be written by spin-orbit torque; a plurality of read word lines, respectively in direct electrical connection with a row of the magnetoresistive storage units; a plurality of write word lines, respectively connecting to a row of the magnetoresistive storage units through selectors; and a plurality of bit lines, respectively connecting to a column of the magnetoresistive storage units, wherein each of the magnetoresistive storage units is connected to the corresponding read word line without a selector in between.

17. The memory circuit according to claim 16 , wherein each of the selectors is configured to be turned on only when the corresponding magnetoresistive storage unit is selected to be programmed.

18. The memory circuit according to claim 16 , wherein the selectors are respectively a two-terminal selector.

19. The memory circuit according to claim 16 , wherein a row of the magnetoresistive storage units are configured to be selected during a read operation.

20. The memory circuit according to claim 16 , wherein one or more in a row of the magnetoresistive storage units is selected during a write operation.